The present invention relates to the field of livestock feeds which include effective amounts of materials which are distasteful to avian species and to avian repellent compositions.
Certain embodiments of the present invention relate to materials and methods for reducing agricultural losses due to avian species, especially many passerine species (e.g., European Starling [Sturnus vulgaris]; Red-winged Blackbird [Agelaius phoeniceus], American Robin [Turdus migratorius], and American Goldfinch [Carduelis tristis]). The cost of starling damage, for example, to an individual farmer from consuming livestock feed can vary considerably from negligible loss up to several thousand dollars during the fall-winter damage season. Palmer, T. K. 1976, "Pest Bird Damage Control in Cattle Feedlots: The Integrated Systems Approach", Proc. Vertebr. Pest Control Conf. Monterey, Calif. 7:17-21. Generally, the large beef cattle feedlots of the west have the most significant losses. However, moderately sized dairy farms in Tennessee feeding 100 to several hundred head of cattle have been estimated to sustain losses of several hundred dollars during a 3-month damage season. Glahn, J. F., (1983) "Blackbird and Starling Depredations at Tennessee Livestock Farms", Proc. Ninth Bird Control Seminar, Bowling Green, Ohio, 125-134. Although starlings can be a problem at hog operations, hog producers need not suffer significant feed loss problems with the use and propr adjustment of flip-top feeders and confinement of swine when feeding. Nevertheless, Tennessee farmers report losses in feedlots of up to 10% due to birds. A similar study in the United Kingdom estimated losses to farmers at up to 12%. Feare, C. J., and K. P. Swannakc, "Starling Damage and its Prevention at an Open-Fronted Calf-Yard," Anim. Prod. 26:259-265 (1978).
The distribution and magnitude of feed loss damage on a national scale has not been studied. However, one study in the winter of 1980 inspected 287 livestock farms in six selected livestock producing counties in Tennessee. Glahn, J. F. supra. Results of this study indicated that 26% of the farms had more than a negligible bird damage problem, including 6% with significant problems where losses exceeding $100 per season would be expected. Based on Tennessee Agricultural Statistics there were 43,000 hog and dairy farms in that state in 1980. However, since the bird damage survey only samples farms with more than twenty head of livestock, the authors estimated the sampled population at 25,900 farms. Therefore, the 6% of the farms that could have benefited from control measures was 1,554. These data are subject to seasonal changes in bird populations, weather conditions, and farm practices, but give some idea of the number of farms that might benefit from bird control measures.
Further analysis of the previous data indicated that the primary factors influencing the distribution of damage were: proximity of roosting starlings to the farm; snow cover; mean temperatures below freezing on the day of inspection; and the number of head of livestock consuming feed. Glahn, J. F., and D.K. Otis, "Factors Influencing the Distribution of Bird Depredations at Livestock Feeding Areas in Tennessee," Bird Damage Research Report No. 231, Denver Wildlife Research Center, Denver, Colo. (1982). Since starlings winter throughout much of the United States, varying degrees of damage at farms might be expected depending on winter weather conditions and size of livestock farms, with most serious problems occurring at large farming operations located in the northern wintering range of the starling. Although the total number of livestock farms in the U.S. is not readily determined, it is known that in 1982 Tennessee had 85,000 dairy farms and 23,000 hog farms with 217,000 milk cows and 750,000 hogs compared with national livestock figures of 11 million milk cows and 53 million swine, respectively. The number of beef cattle on feed or the number of major beef cattle feedlots were not readily available.
It is extremely difficult to quantify the costs associated with the spread of disease to livestock by starlings essentially because it is very difficult to document the effects of avian disease transmission. Two studies have implicated starlings in the spread of transmissible gastroenteritis (TGE) to swine, but no known data exist for other livestock diseases. Gough, P. M., and J. W. Beyer, 1982, "Bird-Vectored Diseases," Proc. Fifth Great Plains Wildlife Damage Control Workshop (R. M. Timm and R. J. Johnson, Eds.), University of Nebraska, Lincoln Neb. pp. 260-272; and Pilchard, E.J. 1965, "Experimental Transmission of Transmissible Gastroenteritis Virus by Starlings: J. Vet. Res. 26(114):1177 1179 The costs of TGE to farmers in terms of stock loss may be substantial. For example, during the winter of 1978-79 a TGE outbreak occurring in southeast Nebraska resulted in the death of 10,000 pigs in one county alone. Because of the possible threat of disease outbreak due to birds, livestock operators and particularly hog producers would be willing to use a material which would keep the birds out of their feedlots. The success of a feed repellent depends both on the effectiveness of the material and the amount of treated feed available to birds.
Few objective estimates of damage by other avian species are available, but in addition to losses from starlings (Sturnus vulgaris), depredation from other species such as red-winged blackbirds at swine and cattle feedlots are considered serious. Besser, J. F. W. C. Royall and J. W. Degrazio, "Baiting Starlings with DRC-1339 at a Cattle Feedlot," J Wildl. Manaqe., 31:48-51 (1967); Besser, J. F. J. W. Degrazio and J.L. Guarino, "Costs of Wintering Starlings and Red-Winged Blackbirds at Feedlots," J Wildl. Manage. 32:179-180 (1968); Feare, C.J., "Cost of Starling Damage of an Intensive Husbandry Unit," Proc. British Insecticide and Fungcide Conf. 8:253-259 (1975); Feare, C.J. (1980), "The Economies of Starling Damage," Econ. of Dam. 2:39-54; Stickley, A.R., "Extended Use of Starlicide in Reducing Bird Damage in Southeastern Feedlots,"Proc. Bird. Cont. Sem. 8:79-89 (1979); and Twedt, D. J. and J. F. Glahn, "Reducing Starling Depredations at Livestock Feeding Operations Through Changes in Management Practices," Proc. Vertebr. Pest. Conf. 10:159-163 (1982). Losses may result from feed contamination and disease transmission or from feed consumption, and problems are exacerbated when nutritionally complete diets are presented in open troughs to which birds have access. See Russell, H.G., "Blackbird Control at Two Army Installations: Environmental Impact Statement," Office Chief Eng., Directorate Facilities Eng., Washington D.C. (1975); Twedt D. J. and J. F. Glahn supra. (1092) and Rickaby, C. D., "A Review of the Nutritional Aspects of Complete Diets for Dairy Cows," ADAS Q. Rev., 29:51-76 (1978). In such a situation, up to 9% of the high protein fraction of the diet can be eaten by birds, thus depriving livestock of a portion of their high value nutrient source and altering the composition of the entire ration. Feare, C. J. and J. T. Wadsworth, "Starling Damage on Farms Using the Complete Diet System of Feeding Dairy Cows," Anim. Prod. 32:179-183 (1981). Efforts to control problem birds at feedlots mainly have involved trapping and/or the use of lethal chemical agents. See Besser, J. F., W. C. Royall and J. W. DeGrazio supra. (1967); Bogadich, V., "The Use of Live Traps to Remove Starlings and Protect Agricultural Products," Proc. Vertebr. Pest. Conf. 3:98-99 (1968); Levingston, P. E., "Winter Starling Control with DRC-1339," Proc. Vertebr. Pest. Conf. 3:89-93 (1967); and Feare, C.J. and J.T. Wadsworth, supra. (1981). These approaches fail to create a sub-optimal environment for avian feeding activity, however, and the birds rapidly reinfest feedlots when control measures are relaxed. See Twedt, D. J. and J. F. Glahn, supra. (1982). Additional problems arise when lethal chemicals such as starlicide (1% C-cholor-p-toludine hydrochloride on poultry pellets) are used, including hazards to non-target animals, development of bait aversion by targeted birds, and increased expense and labor in prebaiting, baiting and monitoring. See Cummingham, D. J., E. W. Schafer and L. K. McConnell, "DRC-1339 and DRC-2698 Residues in Starlings: Preliminary Evaluation of Their Effects on Secondary Hazard Potential," Proc. Bird Contr. Sem. 8:31-37 (1979); and Glahn, J. F., "Use of Starlicide to Reduce Starling Damage at Livestock Feeding Operations," Proc. Great Plains Wildl. Dam. Wrkshp. 5:273-277 (1981). Twedt and Glahn outlined management practices that could be implemented at feedlots to substantially reduce bird depredation. Twedt, D. J. and J. F. Glahn, supra. (1982) Among the suggested practices was the use of feeds that are either unpalatable or that cannot be metabolized by birds. In the latter case, relatively high levels of non-protein nitrogen (e.g., urea) and/or alfalfa might be added. In the former case, certain tastants might be used. Compounds do exist that are unpalatable to birds but readily accepted by mammals. See Welty, J. C., "The Life of Birds" W. B. Saunders Book Co., Philadelphia, Pa., at page 72 (1975).
One compound found to be unpalatable to avian species is dimethyl anthranilate (DMA), a non-toxic food flavoring approved for human consumption but offensive to birds, even when presented at low concentrations. DMA has been suggested as a compound to reduce consumption of normally preferred foods by birds. See U.S. Pat. No. 2,967,128 (Kare).
In addition to the aforementioned losses of livestock feed and losses attributable to disease transmission caused by avian species, significant losses of crops and seeds can be attributed to consumption by such species. Crops which are susceptible to avian consumption include but are not limited to corn, rice, sorghum, grapes, cherries and blueberries.
In addition to the problems encountered in preventing loss of mammalian livestock feeds, crops and seeds to avian species, other problems result from the unwanted ingestion of materials intended for consumption by mammalian species. For example, pesticides such as herbicides, rodenticides and insecticides as well as fertilizers are often applied in pelletized form and persist in such form for long enough periods to be consumed in significant quantities by avian species. If the birds are not killed, they may concentrate lethal agents in such quantities as to cause the secondary poisoning of their predators. Since many of these predators are endangered species, a method of preventing avian prey from ingesting such substances should reduce the incidence of secondary poisonings. See Balcomb, R., "Secondary Poisoning of Red Shouldered Hawks With Carbonfuran:, J. Wildl. Manage. 47(4);1189-1132 (1983). Of course, consumption of the pesticides or fertilizers by avian species can also cause economic hardships to farmers in terms of crop loss and increased pesticide and fertilizer costs.
A primary object of this invention is the provision of a mammalian livestock feed which is not palatable to common avian species, such as starlings and blackbirds.
A further object of this invention is the provision of a method for reducing the amount of livestock feed lost to avian species.
A further object of this invention is the provision of an avian repellent composition which can be applied to crops and seeds to reduce avian consumption of such crops and seeds.
A further object of this invention is the provision of pesticidal and herbicidal compositions which are taste aversive to avian species.
These and other objects of the present invention will become apparent from the following description.